‘Nessie’ could be the answer to spiraling costs of decom

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Seaways Engineering has been involved with designing large Semi-Submersible platforms since the 1980’s and now offers a vast array of platform options.

Their base platform MPSS (Multi-Purpose Semi-Submersible) was originally designed for oil production offshore UK.

At the time it was a huge step forward and as they tested it they quickly understood that it could be adapted to any situation requiring a steady platform.

One of Seaways earliest concepts was a u-shaped vessel, intended for Decommissioning rigs. The assumption being, one day all these platforms will need to be lifted out of place and transported somewhere. That day is fast approaching, and while we have been focused on production, the current oil price has us and everyone else, refocusing on Decommissioning.

Craig Lang – CEO of Seaways Engineering Ltd has more than 50 years’ experience in the marine and offshore industry. Involved in projects such as the Huges Glomar Explorer, Santa Fe’s Reelship Apachie, Conoco Hutton TLP moorings, Dome Sovereign Explorer GVA 4000, Balmoral FPA GVA 5000, Texaco Galley FPF Aker H-3 and Conoco Belanak FPSO.

Some of Seaways inventions include Apache Reelship, steel riser catenary in 1974, Multi-purpose Semi-Submersible in 1980, the first four-column, ring pontoon, semi-submersible designed for shipyard processes which was approved by Conoco and Shell.

Seaways also designed the first ship to lay pipe off a reel, this was called the Apache iY, designed and built in California and has completed over £8 Billion in projects.

Our Idea has been evolved and been refined. We will use our floating platform as a floating dock of sorts. We will attach cable handling equipment to the deck and have our water ballasting system do the heavy lifting. The process is relatively simple when compared to the Pioneering Spirit.

Nessie adopts the idea that has been around for over a century, once used successfully to raise the defeated German fleet, scuttled by Germany in the Scapa Flow after WW1. Using our deep draft vessel as a steady platform we will attach cables, use a diamond cable saw to cut it free of the seabed and lift the entire platform off the seabed and take it to shore for complete dismantle and recycle.

Our low tech approach comes with a relatively low price tag, We expect our first vessel for the smaller installations to be in the region of $140 million. Greatly reduced from the Pioneering Spirit costs of over $3 Billion.

Seaways Nessie system could be build right here in the UK, they have quoted a similar vessel build from Davie Shipyard in Canada for about £85 Million.

Seaways would like to proceed initially with the detailed design of a 60 metre square gated semi-submersible, sized to remove the smaller offshore structures in the Southern North Sea for example the ENI platforms. The vessel will be capable of lifting the entire structure, (topside and jacket) and transport to a shore based facility for recommissioning or scrapping.

It is hoped that this will lead to sufficient interest for the oil companies to provide funds for construction of the semi-submersible. Leading on to the build of the Larger version capable of lifting the larger North Sea Installations.

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